Amplifying system



. 30 1 Aug F. c. BARTON AMPLIFYING SYSTEM med Nov. 14, 1925' Inventor Frederick C. Bar-con; 9 v His Attorney.

rammed Aug. 30,1927.

UNITED STATES rimnnarcx c. neuron, or

rare comrm,

SGHENEC'IADY, NEW YORK, LSSIGNOR TO A CORPORATION 01 NEW YORK.

GENERAL me- AMPLIFYING SYSTEH.

Application filed Novembeifl, 1925. Serial No. 89,200.

My invention relates to apparatus for amplifying voltage impulses and applying them to a sound reproducing device such as a lou speaker, and has for its princi al object the provision'of an improved amplifying system that may be operated by alternating current iuipplied from a house lighting circuit or the In the operation of a sound reproducing device provided with operating and fie'l windings adapted to produce vibration of a diaphragm, it is customary voltage impulses to the operating coil through an amplifying system. This involves the application of different potentials to the cathode heating and anode circuits 0 the amplifiers and to the field winding of the reproducing device. In order to simplify the operation and control of the apparatus it is desirable that these potentials be applied through a single source, that the number of amplifiers be reduced to the smallest number capable of elfecting the proper operation of the reproducing device, and that the excitation of the device be inde endent of variation in the current supplie to its operating coil. In accordance with my invention, these results are accomplished by an arrangement wherein the voltage impulses 99 are amplified through a single amplifier and wherein the excitation of the sound producing device is producedby means of field windings connected in series and shunt with the valve.

My invention will be better understood from the following sidered in connection with the accompanying drawing, and its scope will be pointe out in the appended claims.

I 1 Referring to the drawing, the single figure shows an amplifyin system wherein my invention has been em odied.

This figure shows a sound reproducing device 1 wherein a diaphragm is operated by 4 means of an operating coil located in a v strong magnetic field produced in an annular air gap between poles 3 and 4 of a core member 5 by current transmitted through series and shunt field windings 6 and 7 respectively. For convenience of illustration the diaphragm has been omitted from the drawing .and the core member 5 has been shown diagrammatically.

Voltage impulses from a suitable source are applied to the control circuit of an amphd cathode 11, a

e apply the through a circuit comprising current is-supplied to the transformer 14 and description when cond an the rectifier 18.

exciting current is; not

fier 8 through a transformer 9 and-a liege tive bias resistor 10 which is connected d tween the cathode 11 and grid 12,0f the amplifier 8 and is shunted by a condenser 13' provided for by-passing high frequency currents. A transformer 14 is provided with a primary winding 15 adapted to be connectedto a lighting circuit, a secondary winding 16 adapted to supply the heating current of the secondary winding 17 for supplying the cathode heating current of a thermionic rectifier 1'8, and a secondary winding 19 for supplying the exciting cur rent of thereproduclng devlce 1 and the output current of the amplifier 8. It will be f observed that the cathode 11 and the anode 8 are interconnected the secondary circuit 16, resistor 10, winding 19, rectifier 18, secondary circuit 17, series field coil 6 and the primafiy circuit 21 of a transformer 22; The secon ary circuit 23 of this transformer is connected to the operating coil 2 of the device 1. Pulsation' 1n the current supplied to the anode circuit is prevented by the smoothing condensers 24 and 25 and by the impedances of coil 6-. v

The operation of the apparatus will be readilyunderstood if it be assumed that 20 of the amplifier the voltage impulses to be amplified are applied to the primary circuit of the transformer 9. Under these conditions, the voltage impulses applied to the control or input circuit of the amplifier 8 control the current supplied to the output circuit of the am lifier through the secondary circuit 19 This rectified current is transmitted through the series field wind ing 6 and the firimary circuit 21 of the transformerv 22. ts high fr quency components are kept out of the fiel circuit by the condenser 24 and it is therefore incapable of inducing an electromotive force in the secondarycircuit 23 of the transformer 22.

Variation in the current transmitted through the amplifier 8 is determined by the voltage impulses applied to the grid 12 through the transformer 9 and these variations are utilized to energize the operating 10 coil 2 and produce operation of the sound reproducin device.

It sho 1 be noted that the provision of the shunt coil 7 is of advantage in that the limited by the recti- 0 fied current transmitted through the amplifier but may be made.to have a value high enough to ensure proper operation of the sound reproducing device.

The embodiment of the invention illustrated and described herein has been selected for the purpose of more clearly setting forth the principles involved. It will be apparent, however, that the invention is susceptible of being modified to meet the different conditions encountered in its use and I therefore aim to cover by the appended claims all modifications Within the true spirit and scope of myinvention.

\Vhat I claim as new and desire to secure by Letters Patent of the United States is 1. The combination of a sound reproducing device comprising a plurality. of field circuits and an operating circuit, an amplier provided with a grid for controlling 'the transmission of current between its pulsations to said opera cathode and anode to cause voltage impulses to be applied to said operating circuit, and current supply means connected between said anode and cathode through one of said field circuits and to another of said field circuits independently of said amplifier.

2. The combination of a sound reproducing device comprising a. plurality of field circuits and an operating circuit, an amplifier provided with a grid for producing pulsations in the current transmitted between its cathode and anode, means connected between said cathode and anode for transmitting said ing circuit, a cur rent supply means connected between said anode and cathode through one of said field circuits and saidoperating windingand to another of said field circuits independently of said amplifier and operating winding, and impedance terminals of said field windings for preventing pulsations in the current transmitted therethrough.

3. The combination of a sound reproducmeans connected to the I ing device comprising a plurality of field ing device comprising a plurality of field,

circuits and an operating circuit,an amplifier provided with a grid for controlling the transmission ofcurrent between its cathode aiidanode to cause voltage impulses to be supplied to said operating circuit, current supply means connected between said anode and cathode through one of said field circuits and said operating winding and to another of said field circuits independently of said valve and operating Winding, and means comprising a bias resistor connected between said'cathode and anode for transn'iitting voltage impulses to said grid.

In witness whereof I have hereunto set my hand this 13th day of November, 1925. FREDERICK O. BARTON. 

